重庆三峡库区加工甜橙园土壤养分状况分析

为了解重庆三峡库区加工甜橙园土壤养分含量状况，在重庆7县（区）随机选取132个果园，分析背景土壤和农化土壤pH值、有机质和有效态矿质养分含量。结果显示，分别有56.8%和60.8%的果园背景土壤和农化土壤pH值适宜甜橙生长，农化土壤酸性土比例增加；背景土壤和农化土壤有机质含量不足（<15 mg?Kg-1）的比例分别为77.3%和85.3%，碱解氮处于适宜范围的比例分别为56.8%和61.5%，有效钙过剩（高量和过量）的比例分别为79.6%和76.7%；背景土壤有效磷、钾不足(缺乏和低量)的比例分别为95.4%和72.8%，有效锌、硼不足的比例分别为54.5%和70.5%；农化土壤有效磷、钾不足的比例分别为60.8%和57.6%，有效锌、硼不足比例分别为65.9%和90.7%。背景土壤和农化土壤有效镁、铁、锰及铜不足和过量并存。总体而言，土壤养分状况中等偏差；与背景土壤相比，农化土壤pH值、有机质、有效钙、锌和硼含量下降且缺锌严重，其它养分含量则有所上升。

Nutrient Status Analysis of Soil in processing orange orchards in Three Gorges Reservoir Region of Chongqing

In order to evaluate the soil nutrient status in processing orange orchards in the Three Gorges reservoir region of Chongqing, 132 uncultivated soil samples (US) and 44 cultivated soil samples were collected from 132 orchards distributed in 7 counties in this region, and the soil pH value, organic matter and available nutrient element contents were analyzed. Result showed that the soil pH value of 56.8% US and 60.8% CS was suitable for citrus growth, and the proportion of acid soil in CS increased. The contents of soil organic matter in 77.3% US and in 85.3% CS were in shortage level(<15 mg?Kg-1). 56.8% US and 61.5% CS had suitable available nitrogen content, 79.6% US and 76.7% CS had surplus available Ca. US were 95.4% in shortage of available P, 72.8% in shortage of available K, 54.5% in shortage of available Zn and 70.5% in shortage of available B. CS were 60.8% in shortage of available P, 57.6 in shortage of available K, 65.9% in shortage of available Zn and 90.7% in shortage of available B. While the shortage and surplus of available Mg, Fe, Mn and Cu coexisted in US and CS. In general, nutrient status of soil in processing orange orchards in this region were moderate deviation. Compared with US, the pH value, the contents of organic matter, available Ca, Zn, B in CS decreased and available Zn were severe deficient, while the contents of other nutrients increased.